---

yaml
---
r: 45462
b: refs/heads/master
c: ed5316d
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9d24a81e84cee7cbf4656d178842838ac5ab23a4
+refs/heads/master: ed5316d4457b35c7b4942af028d6b878174264f7

trunk/arch/x86_64/kernel/time.c

@@ -656,6 +656,25 @@ core_initcall(cpufreq_tsc);
  */
 
 #define TICK_COUNT 100000000
+#define TICK_MIN   5000
+
+/*
+ * Some platforms take periodic SMI interrupts with 5ms duration. Make sure none
+ * occurs between the reads of the hpet & TSC.
+ */
+static void __init read_hpet_tsc(int *hpet, int *tsc)
+{
+	int tsc1, tsc2, hpet1;
+
+	do {
+		tsc1 = get_cycles_sync();
+		hpet1 = hpet_readl(HPET_COUNTER);
+		tsc2 = get_cycles_sync();
+	} while (tsc2 - tsc1 > TICK_MIN);
+	*hpet = hpet1;
+	*tsc = tsc2;
+}
+
 
 static unsigned int __init hpet_calibrate_tsc(void)
 {
@@ -666,13 +685,11 @@ static unsigned int __init hpet_calibrate_tsc(void)
 	local_irq_save(flags);
 	local_irq_disable();
 
-	hpet_start = hpet_readl(HPET_COUNTER);
-	rdtscl(tsc_start);
+	read_hpet_tsc(&hpet_start, &tsc_start);
 
 	do {
 		local_irq_disable();
-		hpet_now = hpet_readl(HPET_COUNTER);
-		tsc_now = get_cycles_sync();
+		read_hpet_tsc(&hpet_now, &tsc_now);
 		local_irq_restore(flags);
 	} while ((tsc_now - tsc_start) < TICK_COUNT &&
 		 (hpet_now - hpet_start) < TICK_COUNT);